The present invention relates to a writing instrument.
So called felt pens and sign pens comprising a writing core composed of an ink-absorbing material such as felt and a cylinder containing therein an ink absorber having an ink absorbed therein and being composed of a porous material or an ink tank containing an ink therein have heretofore been marketed and used as writing instruments.
In writing instruments of this type, since the core always contacts an ink absorbed or contained in the ink absorber or ink tank, even if the writing instrument is not used, the ink in the ink absorber or ink tank is perpetually absorbed in the core and the ink absorbed in the core is lost by evaporation from the surface of the core. Further, the ink in the ink absorber or ink tank is expanded when the temperature rises and it leaks excessively from the surface of the core. These are defects of the conventional writing instruments of this type.